Marine birds inhabit an environment that is constantly in motion and that covers 70% of the planet earth. Because of their high metabolic rates they depend on predictable and abundant concentrations of prey. How do these birds locate reliable food sources? At large scales (thousands of kilometers) marine birds rely on areas of high production, but at smaller scales they rely on prey aggregations generated by structured flow patterns. The often surprising ways in which marine birds extract food energy from the oceans are best discovered by developing and then testing hypotheses based on understanding of physical and biological oceanography. Working with George Hunt during the 1980s, I transformed marine ornithology by introducing a new style of research, in which mechanisms based on oceanographic processes were tested against data from directed surveys . We showed that seabirds could be used to develop an understanding of the structure and function of marine ecosystems at upper trophic levels.